i get that a lot... and i have sr1.

 

   i THINK it happens if you nudge the mouse while you are clicking.  it seems to think you are click-dragging?

  and/or... if you are trying to CLOSE a folder, make sure you click on the little triangle, and not on the folder icon or name or anywhere else on that line.  when i started to be more careful about that, it seemed to work better.